This research is concerned with the proactive inhibition effect of non-contingent experience on the retention of a conditioned response learned immediately following the non-contingent environment. The subjects, cats, first experience presentation of "CSs"-- tones or lights--and "UCSs"--shock to right or left forepaw--on a non-contingent (random) schedule, for the number of daily sessions sufficient to produce a CR if the relationship were contingent. Cats are then to be divided into four groups and will experience contingent CS-UCS pairings until a CR is learned to criterion. Group I will have the same stimulus as that of the non-contingent period presentations and will be shocked on the same paw. Group II will also have the same stimulus but will be shocked on the other paw. Group III will have a stimulus different to that of non-contingent experience, but the same paw will be shocked. Group IV will have a stimulus different to that of non-contingent experience and also a different shocked paw. Ten weeks after meeting criterion for this CR, cats would be tested for its retention. Preliminary experimentation indicates a drastic retention loss for the group experiencing the same stimulus and the same response as that of the non-contingent period, compared to the different stimulus-different response group. The other groups will aid in determining whether the retention deficit is due to the stimulus term, or to the response term, or to a generalized non-contingency attitude similar to the concept of learned helplessness. Since the occurrence of proactive inhibition may be used upon spontaneous recovery, the data of the experiment may lead to a better empirical understanding and theoretical interpretation of that phenomenon. The experiment as a whole concerns itself with retention of the conditioned response, a subject little explored.